1. Field of the Invention
This invention relates to electrical wiring conduit devices, and more particularly to inserts for use in floors and the like for segregating high and low voltage wiring egressing from adjacent raceways.
2. Description of the Prior Art
Wire distribution systems which utilize a cellular metal unit having spaced raceways or cells, and an intermediate trough which is enclosed by capping means to provide a third raceway or cell are known. See for example U.S. Pat. Nos. 3,592,956 (FORK); 4,178,469 (FORK). The capping means may comprise plural cover strips and at least one housing (FORK '956) or a protective cover (FORK '469). Each housing or protective cover comprises an activation site at which access to plural electrical services may be gained at a single location in the finished floor structure. Such cellular metal units are used in floor structures wherein the concrete cover above the raceways or cells may vary from one inch (2.54 cm) to 31/4 inches (8.26 cm) or more.
Where the concrete cover thickness is about one inch (2.54 cm), only the FORK '469 protective cover is provided. During activation, the cover is removed to gain access to the raceway and to the third cell. The U-shaped members provide separate vertically presented chambers. Each U-shaped member isolates the wiring egressing from the adjacent raceway from all other wiring.
Where the concrete cover thickness exceeds two inches (5.08 cm), an inverted cup-shaped housing, such as that shown at 42 in U.S. Pat. No. 3,932,696 (FORK et al), is interposed between the protective cover and the metal cellular unit of FORK '469. To accommodate anticipated concrete cover thicknesses of 2 inches (5.04 cm), 21/2 inches (6.35 cm) and 3 inches (7.62 cm) or 31/4 inches (8.26 cm), housings of preselected depths of 11/2 inch (3.81 cm), 15/8 inches (4.13 cm) and 23/8 inches (6.03 cm) are used.
During activation, complete segregation of the high and low voltage wiring is accomplished by installing a distinct partition extension which extends from one of the U-shaped members upwardly into the interior of the housing. The distinct partition plate normally is secured to the top of the U-shaped member and to the top of the housing.
In accordance with present practices different size partition extensions are required to accommodate the various concrete cover thicknesses. Different size partition extensions may be maintained in stock along with partition plates used in other types of inserts. Stock maintenance is, of course, a costly procedure from a materials standpoint. Alternatively, special orders may be sent to a manufacturer for the partition extension--such special orders serving to increase the overall materials cost for each insert. In addition, the double fastening (top and bottom) required to install the partition extension requires added labor time and therefore increases the cost of installing each insert.